Electrochemistry of manganese dioxide in lithium nonaqueous cell; I. X-ray diffractional study on the reduction of electrolytic manganese dioxide

Journal Article · Wed Nov 01 00:00:00 EST 1989 · Journal of the Electrochemical Society; (USA)

DOI:https://doi.org/10.1149/1.2096421· OSTI ID:6912923

Ohzuku, T; Kitagawa, M; Hirai, T ^[1]

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1. Osaka City Univ. (Japan). Faculty of Engineering

X-ray diffractional (XRD) studies were carried out for the electrochemical reduction of heat-treated electolytic MnO{sub 2} (250{degree} and 400{degrees}C for 7 days). A series of XRD examinations indicated that the reaction proceed without the destruction of the core structure of electrolytic manganese dioxide (EMD). The structural changes during the electrochemical reductions of both EMDs were described , assuming a tetragonal sublattice. Both heat-treated electolytic MnO{sub 2}s (HEMDs) behaved similarly in the tetragonal sublattice parameter vs. the reduction degree plots. During the first half of the reduction, HEMD phase having a tetragonal sublattice (a = 4.39 {minus} 4.40 {Angstrom}, c = 2.86 {minus} 2.90 {Angstrom}) was converted into a new Li{sub x} MnO{sub 2} phase having an expanded tetragonal sublattice a = 4.9 {minus} 5.0 {Angstrom}, c = 2.82 {minus} 2.86 {Angstrom}, i.e., in a two-phase reaction. In the 30-90% reduction, the a-axis increased continuously as a function of reduction degree, i.e., in a homogeneous phase reaction. The possible crystal structure of the deep discharge product Li{sub x} MnO{sub 2} (x{gt}0.8) is discussed, assuming a tetragonal unit cell (a = ca. 5 {Angstrom}, c = ca. 2.85 {Angstrom}) having the NiAs-type structure by analogy with Li{sub x} RuO{sub 2}, and an orthorhombic unit cell, i.e., a = 2 {times} b {Angstrom}, b = ca. 5 {Angstrom}, c = ca. 2.85 {Angstrom}.

• OSTI ID: 6912923
• Journal Information: Journal of the Electrochemical Society; (USA), Vol. 136:11; ISSN 0013-4651
• Country of Publication: United States
• Language: English

Related Subjects

25 ENERGY STORAGE
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
36 MATERIALS SCIENCE
CHEMICAL REACTION KINETICS
X-RAY DIFFRACTION
LITHIUM
ELECTRIC BATTERIES
MANGANESE OXIDES
ELECTROCHEMISTRY
CRYSTAL STRUCTURE
NICKEL ARSENIDES
PHASE STUDIES
TETRAGONAL LATTICES
ALKALI METALS
ARSENIC COMPOUNDS
ARSENIDES
CHALCOGENIDES
CHEMISTRY
COHERENT SCATTERING
CRYSTAL LATTICES
DIFFRACTION
ELECTROCHEMICAL CELLS
ELEMENTS
KINETICS
MANGANESE COMPOUNDS
METALS
NICKEL COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PNICTIDES
REACTION KINETICS
SCATTERING
TRANSITION ELEMENT COMPOUNDS
250902* - Energy Storage- Batteries- Performance & Testing
400400 - Electrochemistry
250903 - Energy Storage- Batteries- Materials
Components
& Auxiliaries
360204 - Ceramics
Cermets
& Refractories- Physical Properties